If i put on Python 3 slip on pipes do I need to buy a power commander or new air intake? Or is it just removing the factory pipes and installing the slip on pipes? Or does anybody know a good loud sounding slip on pipe I can use. I have a 2008 FXDC EFI

 

Most likely not if you just put on slip onpipes you will run a little bit leaner but not too much. If you change the air cleaner to a high flow you will definitely need a fuel management device.

 

+1, the conventional wisdom around here is that you don't need to do anything if you only change the slipon mufflers to most of the popular models. Consider a high flow a/c and an ECM air/fuel adjustment of some sort dependent on each other. Best suggestion is to install the mufflers and then check your plugs to make sure they aren't real white indicating an overlean condition. If you see that at any time, you should consider adjusting the air/fuel mix and that's also a good time to add a high flow air cleaner.